The present invention relates generally to a fault detection and diagnostics (FDD) system. The present invention relates more particularly to a FDD system configured to detect and diagnose faults in a refrigeration circuit. The refrigeration circuit may be implemented in a building management system or separate from a building management system.
A building management system (BMS) is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BMS can include a heating, ventilation, and air conditioning (HVAC) system, a security system, a lighting system, a fire alerting system, another system that is capable of managing building functions or devices, or any combination thereof. BMS devices may be installed in any environment (e.g., an indoor area or an outdoor area) and the environment may include any number of buildings, spaces, zones, rooms, or areas. A BMS may include METASYS building controllers or other devices sold by Johnson Controls, Inc., as well as building devices and components from other sources.
Fault detection is an element of some building management systems. Equipment faults increase energy consumption, decrease equipment lifespans and cause other undesirable effects. In some buildings, chillers (e.g., fluid coolers, refrigeration units, etc.) are the single largest energy consumers in the building. Consequently, chiller performance may have a direct and significant impact on overall building energy consumption and efficiency. Traditional fault detection and diagnostic systems evaluate chiller performance by monitoring chiller energy consumption and/or observing a downstream effect that the chiller has on the building environment or other building equipment. It is difficult and challenging to develop fault detection strategies for chillers and other equipment in building management systems.